Author Neil Fletcher
Robins start singing as early as November, the males setting up territories and defending them vigorously. They get themselves really fired up over the colour of their opponents breast, and will even attack a small piece of scarlet cloth even it's hanging up in what they consider to be the wrong place.
They're pretty tireless too, often singing at night, especially if there is a streetlight nearby.
Each phrase of their song lasts two or three seconds, sometimes with longish gaps between, but the striking feature is the high-pitch of the notes, not altogether pleasing to everyone's ear. Each group of notes is almost always ended with a fading, sort of echoey cadence - try thinking of it as sounding a bit like the ’pee-oww’ of bullets ricoché-ing off desert rocks in old Westerns.